// This file is part of Moodle - http://moodle.org/
//
// Moodle is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// Moodle is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with Moodle. If not, see <http://www.gnu.org/licenses/>.
/**
* A javascript module to handle list items drag and drop
*
* Example of usage:
*
* Create a list (for example `<ul>` or `<tbody>`) where each draggable element has a drag handle.
* The best practice is to use the template core/drag_handle:
* $OUTPUT->render_from_template('core/drag_handle', ['movetitle' => get_string('movecontent', 'moodle', ELEMENTNAME)]);
*
* Attach this JS module to this list:
*
* Space between define and ( critical in comment but not allowed in code in order to function
* correctly with Moodle's requirejs.php
*
* For the full list of possible parameters see var defaultParameters below.
*
* The following jQuery events are fired:
* - SortableList.EVENTS.DRAGSTART : when user started dragging a list element
* - SortableList.EVENTS.DRAG : when user dragged a list element to a new position
* - SortableList.EVENTS.DROP : when user dropped a list element
* - SortableList.EVENTS.DROPEND : when user finished dragging - either fired right after dropping or
* if "Esc" was pressed during dragging
*
* @example
* define (['jquery', 'core/sortable_list'], function($, SortableList) {
* var list = new SortableList('ul.my-awesome-list'); // source list (usually <ul> or <tbody>) - selector or element
*
* // Listen to the events when element is dragged.
* $('ul.my-awesome-list > *').on(SortableList.EVENTS.DROP, function(evt, info) {
* console.log(info);
* });
*
* // Advanced usage. Overwrite methods getElementName, getDestinationName, moveDialogueTitle, for example:
* list.getElementName = function(element) {
* return $.Deferred().resolve(element.attr('data-name'));
* }
* });
*
* @module core/sortable_list
* @class core/sortable_list
* @copyright 2018 Marina Glancy
* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
*/
define(['jquery', 'core/log', 'core/autoscroll', 'core/str', 'core/modal_cancel', 'core/modal_events', 'core/notification'],
function($, log, autoScroll, str, ModalCancel, ModalEvents, Notification) {
/**
* Default parameters
*
* @private
* @type {Object}
*/
var defaultParameters = {
targetListSelector: null,
moveHandlerSelector: '[data-drag-type=move]',
isHorizontal: false,
autoScroll: true
};
/**
* Class names for different elements that may be changed during sorting
*
* @private
* @type {Object}
*/
var CSS = {
keyboardDragClass: 'dragdrop-keyboard-drag',
isDraggedClass: 'sortable-list-is-dragged',
isDroppedClass: 'sortable-list-is-dropped',
currentPositionClass: 'sortable-list-current-position',
sourceListClass: 'sortable-list-source',
targetListClass: 'sortable-list-target',
overElementClass: 'sortable-list-over-element'
};
/**
* Test the browser support for options objects on event listeners.
* @return {Boolean}
*/
var eventListenerOptionsSupported = function() {
var passivesupported = false,
options,
testeventname = "testpassiveeventoptions";
// Options support testing example from:
// https://developer.mozilla.org/en-US/docs/Web/API/EventTarget/addEventListener
try {
options = Object.defineProperty({}, "passive", {
// eslint-disable-next-line getter-return
get: function() {
passivesupported = true;
}
});
// We use an event name that is not likely to conflict with any real event.
document.addEventListener(testeventname, options, options);
// We remove the event listener as we have tested the options already.
document.removeEventListener(testeventname, options, options);
} catch (err) {
// It's already false.
passivesupported = false;
}
return passivesupported;
};
/**
* Allow to create non-passive touchstart listeners and prevent page scrolling when dragging
* From: https://stackoverflow.com/a/48098097
*
* @param {string} eventname
* @returns {object}
*/
var registerNotPassiveListeners = function(eventname) {
return {
setup: function(x, ns, handle) {
if (ns.includes('notPassive')) {
this.addEventListener(eventname, handle, {passive: false});
return true;
} else {
return false;
}
}
};
};
if (eventListenerOptionsSupported) {
$.event.special.touchstart = registerNotPassiveListeners('touchstart');
$.event.special.touchmove = registerNotPassiveListeners('touchmove');
$.event.special.touchend = registerNotPassiveListeners('touchend');
}
/**
* Initialise sortable list.
*
* @param {(String|jQuery|Element)} root JQuery/DOM element representing sortable list (i.e. <ul>, <tbody>) or CSS selector
* @param {Object} config Parameters for the list. See defaultParameters above for examples.
* @param {(String|jQuery|Element)} config.targetListSelector target lists, by default same as root
* @param {String} config.moveHandlerSelector CSS selector for a drag handle. By default '[data-drag-type=move]'
* @param {String} config.listSelector CSS selector for target lists. By default the same as root
* @param {(Boolean|Function)} config.isHorizontal Set to true if the list is horizontal (can also be a callback
* with list as an argument)
* @param {Boolean} config.autoScroll Engages autoscroll module for automatic vertical scrolling of the whole page,
* by default true
*/
var SortableList = function(root, config) {
this.info = null;
this.proxy = null;
this.proxyDelta = null;
this.dragCounter = 0;
this.lastEvent = null;
this.config = $.extend({}, defaultParameters, config || {});
this.config.listSelector = root;
if (!this.config.targetListSelector) {
this.config.targetListSelector = root;
}
if (typeof this.config.listSelector === 'object') {
// The root is an element on the page. Register a listener for this element.
$(this.config.listSelector).on('mousedown touchstart.notPassive', $.proxy(this.dragStartHandler, this));
} else {
// The root is a CSS selector. Register a listener that picks up the element dynamically.
$('body').on('mousedown touchstart.notPassive', this.config.listSelector, $.proxy(this.dragStartHandler, this));
}
if (this.config.moveHandlerSelector !== null) {
$('body').on('click keypress', this.config.moveHandlerSelector, $.proxy(this.clickHandler, this));
}
};
/**
* Events fired by this entity
*
* @public
* @type {Object}
*/
SortableList.EVENTS = {
DRAGSTART: 'sortablelist-dragstart',
DRAG: 'sortablelist-drag',
DROP: 'sortablelist-drop',
DRAGEND: 'sortablelist-dragend'
};
/**
* Resets the temporary classes assigned during dragging
* @private
*/
SortableList.prototype.resetDraggedClasses = function() {
var classes = [
CSS.isDraggedClass,
CSS.currentPositionClass,
CSS.overElementClass,
CSS.targetListClass,
];
for (var i in classes) {
$('.' + classes[i]).removeClass(classes[i]);
}
if (this.proxy) {
this.proxy.remove();
this.proxy = $();
}
};
/**
* Calculates evt.pageX, evt.pageY, evt.clientX and evt.clientY
*
* For touch events pageX and pageY are taken from the first touch;
* For the emulated mousemove event they are taken from the last real event.
*
* @private
* @param {Event} evt
*/
SortableList.prototype.calculatePositionOnPage = function(evt) {
if (evt.originalEvent && evt.originalEvent.touches && evt.originalEvent.touches[0] !== undefined) {
// This is a touchmove or touchstart event, get position from the first touch position.
var touch = evt.originalEvent.touches[0];
evt.pageX = touch.pageX;
evt.pageY = touch.pageY;
}
if (evt.pageX === undefined) {
// Information is not present in case of touchend or when event was emulated by autoScroll.
// Take the absolute mouse position from the last event.
evt.pageX = this.lastEvent.pageX;
evt.pageY = this.lastEvent.pageY;
} else {
this.lastEvent = evt;
}
if (evt.clientX === undefined) {
// If not provided in event calculate relative mouse position.
evt.clientX = Math.round(evt.pageX - $(window).scrollLeft());
evt.clientY = Math.round(evt.pageY - $(window).scrollTop());
}
};
/**
* Handler from dragstart event
*
* @private
* @param {Event} evt
*/
SortableList.prototype.dragStartHandler = function(evt) {
if (this.info !== null) {
if (this.info.type === 'click' || this.info.type === 'touchend') {
// Ignore double click.
return;
}
// Mouse down or touch while already dragging, cancel previous dragging.
this.moveElement(this.info.sourceList, this.info.sourceNextElement);
this.finishDragging();
}
if (evt.type === 'mousedown' && evt.which !== 1) {
// We only need left mouse click. If this is a mousedown event with right/middle click ignore it.
return;
}
this.calculatePositionOnPage(evt);
var movedElement = $(evt.target).closest($(evt.currentTarget).children());
if (!movedElement.length) {
// Can't find the element user wants to drag. They clicked on the list but outside of any element of the list.
return;
}
// Check that we grabbed the element by the handle.
if (this.config.moveHandlerSelector !== null) {
if (!$(evt.target).closest(this.config.moveHandlerSelector, movedElement).length) {
return;
}
}
evt.stopPropagation();
evt.preventDefault();
// Information about moved element with original location.
// This object is passed to event observers.
this.dragCounter++;
this.info = {
element: movedElement,
sourceNextElement: movedElement.next(),
sourceList: movedElement.parent(),
targetNextElement: movedElement.next(),
targetList: movedElement.parent(),
type: evt.type,
dropped: false,
startX: evt.pageX,
startY: evt.pageY,
startTime: new Date().getTime()
};
$(this.config.targetListSelector).addClass(CSS.targetListClass);
var offset = movedElement.offset();
movedElement.addClass(CSS.currentPositionClass);
this.proxyDelta = {x: offset.left - evt.pageX, y: offset.top - evt.pageY};
this.proxy = $();
var thisDragCounter = this.dragCounter;
setTimeout($.proxy(function() {
// This mousedown event may in fact be a beginning of a 'click' event. Use timeout before showing the
// dragged object so we can catch click event. When timeout finishes make sure that click event
// has not happened during this half a second.
// Verify dragcounter to make sure the user did not manage to do two very fast drag actions one after another.
if (this.info === null || this.info.type === 'click' || this.info.type === 'keypress'
|| this.dragCounter !== thisDragCounter) {
return;
}
// Create a proxy - the copy of the dragged element that moves together with a mouse.
this.createProxy();
}, this), 500);
// Start drag.
$(window).on('mousemove touchmove.notPassive mouseup touchend.notPassive', $.proxy(this.dragHandler, this));
$(window).on('keypress', $.proxy(this.dragcancelHandler, this));
// Start autoscrolling. Every time the page is scrolled emulate the mousemove event.
if (this.config.autoScroll) {
autoScroll.start(function() {
$(window).trigger('mousemove');
});
}
this.executeCallback(SortableList.EVENTS.DRAGSTART);
};
/**
* Creates a "proxy" object - a copy of the element that is being moved that always follows the mouse
* @private
*/
SortableList.prototype.createProxy = function() {
this.proxy = this.info.element.clone();
this.info.sourceList.append(this.proxy);
this.proxy.removeAttr('id').removeClass(CSS.currentPositionClass)
.addClass(CSS.isDraggedClass).css({position: 'fixed'});
this.proxy.offset({top: this.proxyDelta.y + this.lastEvent.pageY, left: this.proxyDelta.x + this.lastEvent.pageX});
};
/**
* Handler for click event - when user clicks on the drag handler or presses Enter on keyboard
*
* @private
* @param {Event} evt
*/
SortableList.prototype.clickHandler = function(evt) {
if (evt.type === 'keypress' && evt.originalEvent.keyCode !== 13 && evt.originalEvent.keyCode !== 32) {
return;
}
if (this.info !== null) {
// Ignore double click.
return;
}
// Find the element that this draghandle belongs to.
var clickedElement = $(evt.target).closest(this.config.moveHandlerSelector),
sourceList = clickedElement.closest(this.config.listSelector),
movedElement = clickedElement.closest(sourceList.children());
if (!movedElement.length) {
return;
}
evt.preventDefault();
evt.stopPropagation();
// Store information about moved element with original location.
this.dragCounter++;
this.info = {
element: movedElement,
sourceNextElement: movedElement.next(),
sourceList: sourceList,
targetNextElement: movedElement.next(),
targetList: sourceList,
dropped: false,
type: evt.type,
startTime: new Date().getTime()
};
this.executeCallback(SortableList.EVENTS.DRAGSTART);
this.displayMoveDialogue(clickedElement);
};
/**
* Finds the position of the mouse inside the element - on the top, on the bottom, on the right or on the left\
*
* Used to determine if the moved element should be moved after or before the current element
*
* @private
* @param {Number} pageX
* @param {Number} pageY
* @param {jQuery} element
* @returns {(Object|null)}
*/
SortableList.prototype.getPositionInNode = function(pageX, pageY, element) {
if (!element.length) {
return null;
}
var node = element[0],
offset = 0,
rect = node.getBoundingClientRect(),
y = pageY - (rect.top + window.scrollY),
x = pageX - (rect.left + window.scrollX);
if (x >= -offset && x <= rect.width + offset && y >= -offset && y <= rect.height + offset) {
return {
x: x,
y: y,
xRatio: rect.width ? (x / rect.width) : 0,
yRatio: rect.height ? (y / rect.height) : 0
};
}
return null;
};
/**
* Check if list is horizontal
*
* @param {jQuery} element
* @return {Boolean}
*/
SortableList.prototype.isListHorizontal = function(element) {
var isHorizontal = this.config.isHorizontal;
if (isHorizontal === true || isHorizontal === false) {
return isHorizontal;
}
return isHorizontal(element);
};
/**
* Handler for events mousemove touchmove mouseup touchend
*
* @private
* @param {Event} evt
*/
SortableList.prototype.dragHandler = function(evt) {
evt.preventDefault();
evt.stopPropagation();
this.calculatePositionOnPage(evt);
// We can not use evt.target here because it will most likely be our proxy.
// Move the proxy out of the way so we can find the element at the current mouse position.
this.proxy.offset({top: -1000, left: -1000});
// Find the element at the current mouse position.
var element = $(document.elementFromPoint(evt.clientX, evt.clientY));
// Find the list element and the list over the mouse position.
var mainElement = this.info.element[0],
isNotSelf = function() {
return this !== mainElement;
},
current = element.closest('.' + CSS.targetListClass + ' > :not(.' + CSS.isDraggedClass + ')').filter(isNotSelf),
currentList = element.closest('.' + CSS.targetListClass),
proxy = this.proxy,
isNotProxy = function() {
return !proxy || !proxy.length || this !== proxy[0];
};
// Add the specified class to the list element we are hovering.
$('.' + CSS.overElementClass).removeClass(CSS.overElementClass);
current.addClass(CSS.overElementClass);
// Move proxy to the current position.
this.proxy.offset({top: this.proxyDelta.y + evt.pageY, left: this.proxyDelta.x + evt.pageX});
if (currentList.length && !currentList.children().filter(isNotProxy).length) {
// Mouse is over an empty list.
this.moveElement(currentList, $());
} else if (current.length === 1 && !this.info.element.find(current[0]).length) {
// Mouse is over an element in a list - find whether we should move the current position
// above or below this element.
var coordinates = this.getPositionInNode(evt.pageX, evt.pageY, current);
if (coordinates) {
var parent = current.parent(),
ratio = this.isListHorizontal(parent) ? coordinates.xRatio : coordinates.yRatio,
subList = current.find('.' + CSS.targetListClass),
subListEmpty = !subList.children().filter(isNotProxy).filter(isNotSelf).length;
if (subList.length && subListEmpty && ratio > 0.2 && ratio < 0.8) {
// This is an element that is a parent of an empty list and we are around the middle of this element.
// Treat it as if we are over this empty list.
this.moveElement(subList, $());
} else if (ratio > 0.5) {
// Insert after this element.
this.moveElement(parent, current.next().filter(isNotProxy));
} else {
// Insert before this element.
this.moveElement(parent, current);
}
}
}
if (evt.type === 'mouseup' || evt.type === 'touchend') {
// Drop the moved element.
this.info.endX = evt.pageX;
this.info.endY = evt.pageY;
this.info.endTime = new Date().getTime();
this.info.dropped = true;
this.info.positionChanged = this.hasPositionChanged(this.info);
var oldinfo = this.info;
this.executeCallback(SortableList.EVENTS.DROP);
this.finishDragging();
if (evt.type === 'touchend'
&& this.config.moveHandlerSelector !== null
&& (oldinfo.endTime - oldinfo.startTime < 500)
&& !oldinfo.positionChanged) {
// The click event is not triggered on touch screens because we call preventDefault in touchstart handler.
// If the touchend quickly followed touchstart without moving, consider it a "click".
this.clickHandler(evt);
} else if (oldinfo.positionChanged) {
mainElement.classList.add(CSS.isDroppedClass);
}
}
};
/**
* Checks if the position of the dragged element in the list has changed
*
* @private
* @param {Object} info
* @return {Boolean}
*/
SortableList.prototype.hasPositionChanged = function(info) {
return info.sourceList[0] !== info.targetList[0] ||
info.sourceNextElement.length !== info.targetNextElement.length ||
(info.sourceNextElement.length && info.sourceNextElement[0] !== info.targetNextElement[0]);
};
/**
* Moves the current position of the dragged element
*
* @private
* @param {jQuery} parentElement
* @param {jQuery} beforeElement
*/
SortableList.prototype.moveElement = function(parentElement, beforeElement) {
var dragEl = this.info.element;
if (beforeElement.length && beforeElement[0] === dragEl[0]) {
// Insert before the current position of the dragged element - nothing to do.
return;
}
if (parentElement[0] === this.info.targetList[0] &&
beforeElement.length === this.info.targetNextElement.length &&
beforeElement[0] === this.info.targetNextElement[0]) {
// Insert in the same location as the current position - nothing to do.
return;
}
if (beforeElement.length) {
// Move the dragged element before the specified element.
parentElement[0].insertBefore(dragEl[0], beforeElement[0]);
} else if (this.proxy && this.proxy.parent().length && this.proxy.parent()[0] === parentElement[0]) {
// We need to move to the end of the list but the last element in this list is a proxy.
// Always leave the proxy in the end of the list.
parentElement[0].insertBefore(dragEl[0], this.proxy[0]);
} else {
// Insert in the end of a list (when proxy is in another list).
parentElement[0].appendChild(dragEl[0]);
}
// Save the current position of the dragged element in the list.
this.info.targetList = parentElement;
this.info.targetNextElement = beforeElement;
this.executeCallback(SortableList.EVENTS.DRAG);
};
/**
* Finish dragging (when dropped or cancelled).
* @private
*/
SortableList.prototype.finishDragging = function() {
this.resetDraggedClasses();
if (this.config.autoScroll) {
autoScroll.stop();
}
$(window).off('mousemove touchmove.notPassive mouseup touchend.notPassive', $.proxy(this.dragHandler, this));
$(window).off('keypress', $.proxy(this.dragcancelHandler, this));
this.executeCallback(SortableList.EVENTS.DRAGEND);
this.info = null;
};
/**
* Executes callback specified in sortable list parameters
*
* @private
* @param {String} eventName
*/
SortableList.prototype.executeCallback = function(eventName) {
this.info.element.trigger(eventName, this.info);
};
/**
* Handler from keypress event (cancel dragging when Esc is pressed)
*
* @private
* @param {Event} evt
*/
SortableList.prototype.dragcancelHandler = function(evt) {
if (evt.type !== 'keypress' || evt.originalEvent.keyCode !== 27) {
// Only cancel dragging when Esc was pressed.
return;
}
// Dragging was cancelled. Return item to the original position.
this.moveElement(this.info.sourceList, this.info.sourceNextElement);
this.finishDragging();
};
/**
* Returns the name of the current element to be used in the move dialogue
*
* @public
* @param {jQuery} element
* @return {Promise}
*/
SortableList.prototype.getElementName = function(element) {
return $.Deferred().resolve(element.text());
};
/**
* Returns the label for the potential move destination, i.e. "After ElementX" or "To the top of the list"
*
* Note that we use "after" in the label for better UX
*
* @public
* @param {jQuery} parentElement
* @param {jQuery} afterElement
* @return {Promise}
*/
SortableList.prototype.getDestinationName = function(parentElement, afterElement) {
if (!afterElement.length) {
return str.get_string('movecontenttothetop', 'moodle');
} else {
return this.getElementName(afterElement)
.then(function(name) {
return str.get_string('movecontentafter', 'moodle', name);
});
}
};
/**
* Returns the title for the move dialogue ("Move elementY")
*
* @public
* @param {jQuery} element
* @param {jQuery} handler
* @return {Promise}
*/
SortableList.prototype.getMoveDialogueTitle = function(element, handler) {
if (handler.attr('title')) {
return $.Deferred().resolve(handler.attr('title'));
}
return this.getElementName(element).then(function(name) {
return str.get_string('movecontent', 'moodle', name);
});
};
/**
* Returns the list of possible move destinations
*
* @private
* @return {Promise}
*/
SortableList.prototype.getDestinationsList = function() {
var addedLists = [],
targets = $(this.config.targetListSelector),
destinations = $('<ul/>').addClass(CSS.keyboardDragClass),
result = $.when().then(function() {
return destinations;
}),
createLink = $.proxy(function(parentElement, beforeElement, afterElement) {
if (beforeElement.is(this.info.element) || afterElement.is(this.info.element)) {
// Can not move before or after itself.
return;
}
if ($.contains(this.info.element[0], parentElement[0])) {
// Can not move to its own child.
return;
}
result = result
.then($.proxy(function() {
return this.getDestinationName(parentElement, afterElement);
}, this))
.then(function(txt) {
var li = $('<li/>').appendTo(destinations);
var a = $('<a href="#"/>').attr('data-core_sortable_list-quickmove', 1).appendTo(li);
a.data('parent-element', parentElement).data('before-element', beforeElement).text(txt);
return destinations;
});
}, this),
addList = function() {
// Destination lists may be nested. We want to add all move destinations in the same
// order they appear on the screen for the user.
if ($.inArray(this, addedLists) !== -1) {
return;
}
addedLists.push(this);
var list = $(this),
children = list.children();
children.each(function() {
var element = $(this);
createLink(list, element, element.prev());
// Add all nested lists.
element.find(targets).each(addList);
});
createLink(list, $(), children.last());
};
targets.each(addList);
return result;
};
/**
* Displays the dialogue to move element.
* @param {jQuery} clickedElement element to return focus to after the modal is closed
* @private
*/
SortableList.prototype.displayMoveDialogue = function(clickedElement) {
ModalCancel.create({
title: this.getMoveDialogueTitle(this.info.element, clickedElement),
body: this.getDestinationsList()
}).then($.proxy(function(modal) {
var quickMoveHandler = $.proxy(function(e) {
e.preventDefault();
e.stopPropagation();
this.moveElement($(e.currentTarget).data('parent-element'), $(e.currentTarget).data('before-element'));
this.info.endTime = new Date().getTime();
this.info.positionChanged = this.hasPositionChanged(this.info);
this.info.dropped = true;
clickedElement.focus();
this.executeCallback(SortableList.EVENTS.DROP);
modal.hide();
}, this);
modal.getRoot().on('click', '[data-core_sortable_list-quickmove]', quickMoveHandler);
modal.getRoot().on(ModalEvents.hidden, $.proxy(function() {
// Always destroy when hidden, it is generated dynamically each time.
modal.getRoot().off('click', '[data-core_sortable_list-quickmove]', quickMoveHandler);
modal.destroy();
this.finishDragging();
}, this));
modal.setLarge();
modal.show();
return modal;
}, this)).catch(Notification.exception);
};
return SortableList;
});